WEBVTT
Kind: captions
Language: en

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♪ Electricity ♪

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♪ AC ♪
♪ Electricity ♪
♪ DC ♪

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We're demonstrating the new ACT001
ultraminiature inline analog current sensor.

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We'll test the transfer function,  
and show an AC and a DC application.

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The sensor comes in a six-pin 
DFN package.

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It's 2.5 millimeters--
less than a tenth of an inch--square.

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It has tunneling magnetoresistor 
sensor elements
with a differential output,

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and an integrated current strap.

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To test the transfer function,
we'll connect the input to a signal generator...

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The output is connected to an oscilloscope,

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and the sensor is powered by a battery.

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We'll turn on the signal generator
to sweep the current.

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The x-axis shows the current sweep,

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and the y-axis is the sensor output.

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As the 'scope shows, 
the ACT001 is highly linear

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past the maximum signal generator output,
which is +/-238 milliamps full scale.

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These sensors are fully isolated
so they can be used for line-voltage sensing.

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They're accurate for low current,
as we show with just a four-watt motor.

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The RMS current is only 30 milliamps, 
but we have a clear signal

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showing the characteristic triangular current 
waveform of a synchronous motor.

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And if we change the load,
the sensor shows the changing waveform.

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To demonstrate isolation,

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we deliberately put the sensor 
in the hot side of the line.

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So there are dangerous voltages 
on the sense wires,

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but the sensor output is perfectly safe.

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You sure wouldn't want to connect a 
non-isolated current sensor to an oscilloscope.

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Finally, let's look at a DC application.

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In addition to sensing current,

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the ACT001 output is ratiometric 
with its power supply,

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so it can be used as 
a single-component power sensor,

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with no multiplication required.

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Connected like this, 
the sensor output is proportional

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to both the motor voltage and motor current,
so the output is proportional to power,

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and since the sensor has no active elements,

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it's accurate down to zero supply.

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As you can see, the power-- 
as indicated by the meter--

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increases faster than the current 
as we increase the voltage,

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which is what we'd expect.

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How does the sensor work?

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As the current increases,

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these two TMR resistors get bigger;

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these two decrease;

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and that causes 
the differential output voltage to increase.

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Things are reversed
for a negative current.

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So we've seen that
the ACT001 current sensor has:

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a wide linear range 
and senses polarity as well as current;

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it has a wide supply range;

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with a ratiometric output 
for power measurement.

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It's fully isolated;

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and it's ultraminiature.

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Click, email, or call 
for more information,

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or to order parts.